1. Field of the Invention
The present invention relates to a seat-occupant restraining apparatus which expands a belt for restraining a seat occupant in a seat at the time of a collision of a vehicle, the belt being expanded with a high-pressure gas supplied from an inflator.
2. Description of the Related Art
An air belt assembly which includes a bag accommodated in a seat belt so that the bag is expanded to gently restrain a seat occupant at the time of a collision of a vehicle is already known, for example, from Japanese Patent Application Laid-Open No. 6-56001.
The bag of such an air belt assembly has a vent hole, and after the bag has been expanded, the internal pressure of the bag is adjusted to an appropriate value by discharging an extra high-pressure gas through the vent hole.
However, the vent hole, which is a simple opening formed in the bag and which automatically opens in the process of expansion of the folded bag, involves the problem that if the manner of the expansion of the folded bag varies, the timing or extent of opening of the vent hole does not become constant and it becomes difficult to discharge the extra high-pressure gas at an appropriate time.
A buckle assembly, to which a tongue device that is provided on a belt is connected, is pivotally supported on a seat base to be swingable forwardly and rearwardly, in order to compensate for a variation in the angle of the belt due to the forward or rearward position of a seat or the shape of the body of the seat occupant, when the seat occupant wears the seat belt assembly. For the same reasons in the air belt assembly as well, the buckle assembly needs to be supported pivotally to be swingable forwardly and rearwardly.
FIG. 14 shows the essential portion of a conventional air belt assembly. A buckle assembly 04, to which a tongue device 03 is connected, provided at one end of each of a shoulder belt 01 and a lap belt 02, is pivotally supported on a seat base 05 by a pivot pin 06 to be swingable forwardly and rearwardly. At the time of a collision of the vehicle, the high-pressure gas, produced by an inflator 07, integrally provided on the buckle assembly 04, is supplied to the shoulder belt 01 through the buckle assembly 04 and the tongue device 03, thereby expanding the shoulder belt 01 to gently restrain the seat occupant. In such a conventional air belt assembly, since the inflator 07 is integrally provided on the buckle assembly 04, as the buckle assembly 04 pivots about the pivot pin 06, the inflator 07 integrally pivots. This leads to the problem that limitations are put on the design because it is necessary to avoid the interference of the inflator 07 with other members.
The magnitudes of the shocks due to collisions of vehicles widely range from a small shock, for which a seat occupant can be fully restrained with only a normal seat belt, to a large shock, for which it is necessary to produce the largest possible restraining force. However, in a case where a seat occupant can be fully restrained, for example, merely by operating an air belt assembly without operating an air bag assembly, if both the air bag assembly and the air belt assembly are operated at the same time, the air bag assembly, which originally need not be used, will be wastefully used and the problem of an economic burden to a user will occur.
The present invention has been made in view of the above-described problems, and a first object of the present invention is to realize a stable air vent function superior to that of a vent hole, without providing a vent hole in the bag of an air belt assembly.
A second object of the present invention is to allow a swinging motion of a buckle assembly, while avoiding the interference of an inflator with other members in an air belt assembly.
A third object of the present invention is to avoid wasteful use of an air bag assembly and an air betassembly, while ensuring necessary and sufficient restraining force, by controlling the operations of the air bag assembly and the air belt assembly according to the magnitude of shock applied to a vehicle.
To achieve the above-described first object, according to a first feature of the present invention, a seat-occupant restraining apparatus is provided which comprises a bag accommodated in a belt for restraining a seat occupant in a seat, and when a vehicle collides, expands the bag with a high-pressure gas produced by an inflator, wherein a relief valve, which opens according to an increase in an internal pressure of the bag, is provided in a gas passage for supplying the high-pressure gas from the inflator to the bag.
According to the above-described construction, if the inflator ignites at the time of a collision of the vehicle, a produced high-pressure gas is supplied to the bag accommodated in the belt and the belt is expanded so that the seat occupant can be gently restrained. If the bag completes expanding due to the high-pressure gas from the inflator and the internal pressure of the bag reaches the valve-opening pressure of the relief valve, the relief valve opens to discharge an extra high-pressure gas from the bag. Accordingly, not only is it possible to control the internal pressure of the bag to an appropriate value without causing variations, but it is also possible to freely set the gas-discharging direction of the relief valve and discharge the high-pressure gas in a direction away from the body of the seat occupant.
To achieve the first object described above, according to a second feature of the present invention, a seat-occupant restraining apparatus is provided which comprises a bag accommodated in a belt for restraining a seat occupant in a seat, and when a vehicle collides, expands the bag with a high-pressure gas produced by an inflator, wherein a solenoid valve, which opens with a time delay after an ignition of the inflator, is provided in a gas passage for supplying the high-pressure gas from the inflator to the bag.
According to the above-described construction, if the inflator ignites at the time of a collision of the vehicle, a produced high-pressure gas is supplied to the bag accommodated in the belt and the belt is expanded so that the seat occupant can be gently restrained. If a sufficient amount of time, which is necessary for the bag to complete expanding, passes after the inflator ignites, the solenoid valve opens to discharge an extra high-pressure gas from the bag. Accordingly, not only is it possible to control the internal pressure of the bag to an appropriate value without causing variations, but it is also possible to freely set the gas-discharging direction of a relief valve and discharge the high-pressure gas in a direction away from the body of the seat occupant.
To achieve the first object described above, according to a third feature of the present invention, a seat-occupant restraining apparatus is provided which comprises a bag accommodated in a belt for restraining a seat occupant in a seat, and when a vehicle collides, expands the bag with a high-pressure gas produced by an inflator, wherein a relief valve, which opens according to an crease in an internal pressure of the bag, is provided in a gas passage for discharging the high-pressure gas of the bag into the atmosphere.
According to the above-described construction, if the inflator ignites at the time of a collision of the vehicle, a produced high-pressure gas is supplied to the bag accommodated in the belt and the bag is expanded so that the seat occupant can be gently restrained. If the bag completes expanding due to the high-pressure gas from the inflator and the internal pressure of the bag reaches the valve-opening pressure of the relief valve, the relief valve opens to discharge an extra high-pressure gas from the bag. Accordingly, not only is it possible to control the internal pressure of the bag to an appropriate value without causing variations, but it is also possible to freely set the gas-discharging direction of the relief valve and discharge the high-pressure gas in a direction away from the body of the seat occupant.
To achieve the first object described above, according to a fourth feature of the present invention, a seat-occupant restraining apparatus is provided which comprises a bag accommodated in a belt for restraining a seat occupant in a seat, and when a vehicle collides, expands the bag with a high-pressure gas produced by an inflator, wherein a solenoid valve, which opens with a time delay after an ignition of the inflator, is provided in a gas passage for discharging the high-pressure gas of the bag into the atmosphere.
According to the above described construction, if the inflator ignites at the time of a collision of the vehicle, a produced high-pressure gas is supplied to the bag accommodated in the belt and the bag is expanded so that the seat occupant can be gently restrained. If a sufficient amount of time, which is necessary for the bag to complete expanding, passes after the inflator ignites, the solenoid valve opens to discharge an extra high-pressure gas from the bag. Accordingly, not only is it possible to control the internal pressure of the bag to an appropriate value without causing variations, but it is also possible to freely set the gas-discharging direction of a relief valve and discharge the high-pressure gas in a direction away from the body of the seat occupant.
To achieve the second object described above, according to a fifth feature of the present invention, a seat-occupant restraining apparatus is provided comprising: a belt in which a bag, which is expandable, is accommodated and which is supported at its one end on a fixed portion; a tongue device which is provided at the other end of the belt; a buckle assembly which is supported on the fixed portion to be swingable forwardly and rearwardly and to which the tongue device is connected; an inflator which is supported on the fixed portion for producing a high-pressure gas; and a flexible pipe which connects the inflator to the buckle assembly, wherein when a vehicle collides, the bag is expanded by supplying the high-pressure gas produced by the inflator to the bag through the flexible pipe, the buckle assembly, and the tongue device.
According to the above-described construction, when the seat occupant sits in a seat and connects the tongue device to the buckle assembly, even if the angle of the belt varies according to the forward or rearward position of the seat or the shape of the body of the seat occupant, the buckle assembly swings together with the tongue device and a variation in the angle of the belt can be absorbed. Even if the buckle assembly swings, the inflator, fixed to a fixed portion, does not swing and has no possibility of interfering with another member. In addition, the high-pressure gas can be smoothly supplied from the inflator to the buckle assembly via the flexible pipe.
To achieve the third object described above, according to a sixth feature of the present invention, a seat-occupant restraining apparatus is provided comprising: an air bag inflator, which produces a high-pressure gas; an air bag, which is expanded by the high-pressure gas produced by the air bag inflator and expands in front of a seat occupant sitting in a seat; an air belt inflator, which produces a high-pressure gas; an air belt, which is expanded by the high-pressure gas produced by the air belt inflator in the state of restraining the seat occupant in the seat; shock detecting means for detecting a shock of a collision of a vehicle; and control means for controlling an operation of the air bag inflator and an operation of the air belt inflator on the basis of an output of the shock detecting means, wherein if the shock detected by the shock detecting means is less than a first threshold the control means does not operate any one of the air bag inflator and the air belt inflator, wherein if the shock is not less than the first threshold and less than a second threshold greater than the first threshold, the control means does not operate the air bag inflator and operates the air belt inflator, and wherein if the shock is not less than the second threshold, the control means operates both the air bag inflator and the air belt inflator.
According to the above-described construction, if the shock of a collision of the vehicle is less than the first threshold and it is not necessary to strongly restrain the seat occupant, neither the air bag nor the air belt is expanded, and the seat occupant is restrained with only the air belt which functions as a mere seat belt. If the shock is not less than the first threshold and less than the second threshold and it is necessary to comparatively strongly restrain the seat occupant, only the air belt is expanded to produce the necessary and sufficient restraining force. If the shock is not less than the second threshold and it is necessary to strongly restrain the seat occupant, the air bag and the air belt are expanded to produce the maximum restraining force. In this manner, by inhibiting expansion of the air bag or the air belt when sufficient restraining force is obtained with other restraining means, it is possible to prevent wasteful operation of the air bag or the air belt to ease the economic burden on a user.
In the embodiment, the first threshold corresponds to the shock with which the vehicle collides head-on against a rigid wall at 16 km/h, while the second threshold corresponds to the shock with which the vehicle collides head-on against a rigid wall at 24 km/h. However, the values of these thresholds are a matter of design choice which can be appropriately varied.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawing figures.